Hi, I am tring to identify the remains of a possable civil war seacost cannon. In a resent archeaological excavation in San Juan Bay, Puerto Rico we found the 6'9" remains of an iron 19 century muzzle loading cannon (its missing about three feet of the tube)It has the proportions of a 8 inch columbiad but has a round button on a flat base. It has an 8 inch bore and its chase appear to have been shot off. It has very clean and simple lines with a slit differance in diameter between the first and second reinforce. It has no rings, ogees, astragale or fillete. It has trunnions and trunnion shoulders. It is not rifled. After cleanning I will try to identify any possable marks and to determine if it has a breech chamber. I have may pictures but don't know how to upload them here.